Electrostatic dust filter



Jan. 9, 1968 w. STEUERNAGEL ETAL IN VENTORS F ILJ Walter Szuerna FiledDec. 28, 1966 bwez %sho/d AT'TO NEY:

United States Patent 1 Claim. of. 55-130 ABSTRACT OF THE DISCLOSURE Thevertically spaced spark points on an emitting electrode are positionedin staggered relationship to the vertically spaced spark points on anemitting electrode adjacent thereto to reduce the interference in theelectrical fields produced by the spark points.

Electrostatic dust filters are composed of walls of precipitatingelectrodes forming a gas passageway in which are mounted spark oremitting electrodes which have spark points for producing the corona forthe electrical field. In order to improve upon the precipitation ofdust, these spark points are directed toward definite precipitatingelectrode surface portions. For example, such spark points are directedtoward the dust collecting pockets formed in the precipitatingelectrodes. In many cases, it is customary to displace the emittingelectrode by the length of the spark point from the center line of thegas duct in order to get all of the spark points on one line. Experiencehas shown that when the spark points are not positioned at acorresponding distance from one another, the electrical field isdisturbed which causes a detrimental effect on the amount of dustprecipitation. Also, the displacement of the individual emittingelectrode wires from the center line of the gas passageway results indifficulties in mounting the emitting electrode frames and/ or theemitting electrodes within the frame.

Nothing is gained by providing a plurality of emitting electrodes or asmany as possible having spark points for any chosen shape of theprecipitating electrodes in order to attempt an increase in the amountof dust precipitation. Experience has shown that in most cases the exactopposite results. Even though many efforts have been made to positionthe spark points between correspondingly formed precipitating electrodeplates, it has been found again and again that no noteworthy improvementin the amount of dust precipitation occurs when compared with theexpense of construction.

In this invention, it has been surprisingly found that, with a certainshape of a precipitating electrode, it is possible to arrange theemitting electrodes so that their spark points produce optimum dustprecipitation together with satisfactory electrical, gas flow andvibration characteristics of the precipitating electrodes.

According to this invention, a gas passageway is formed between twowalls composed of rows of individual precipitating electrodes. Eachelectrode is composed of a central web, side portions lying in a planeoffset from the plane of the web, S-shaped bent portions joining theside portions to the web, with the S-shaped portions being slightlycurved over the web, and with the side portions each having a widthabout one-half of the width of the web. Edge portions on the sideportions are curved toward the web in the form of hooks and theindividual precipitating electrodes are hooked together by such edgeportions. The spark emitting electrodes are mounted in the gaspassageway between the precipitating walls with the spark points of twoemitting electrodes directed toward a web formed dust collecting pocketand the spark points of one 3,362,135 Patented Jan. 9, 1968 emittingelectrode directed toward a side portion dust collecting pocket, andwith the spark points of adjacent emitting electrodes being positionedat different vertical levels, respectively.

This filter arrangement, as shown by experience, produces an improvedamount of dust precipitation over heretofore used arrangements by theasymmetrical positioning of the spark points to the left, right, right,left, in the direction of gas flow. By vertically separating the sparkpoints directed to the larger web dust pocket, the interference in theelectrical field caused by the points is almost completely eliminated.Another advantage lies in the improved utilization of the oppositelyfaced precipitating electrode wall surfaces.

The means by which the objects of the invention are obtained aredescribed more fully with reference to the accompanying drawings inwhich:

FIGURE 1 is a front elevational view of a row of precipitatingelectrodes forming an electrode wall; and

FIGURE 2 is a cross-sectional view through a gas passageway extendingbetween two electrode walls formed of rows of individual precipitatingelectrodes.

Each individual precipitating electrode 1 has a center Web 2 which isoffset from the plane containing the two side portions 3. These sideportions are connected to the web by means of S-shaped portions 4. Theedges 5 of the side portions 3 are bent inwardly toward the web in theform of books. As shown in the drawings, each side portion 3 has a widthequal to about one-half of the width of the web 2, Crimped rib 6 can beformed in the web 2 for additional reinforcement. The emitting or sparkelectrodes 7 in the center of the passageway between the two electrodewalls have emitting points 8 directed so that they point to the pocketformed by the Web or to a pocket formed by the side portions. One sparkelectrode with its points is always provided for the pockets formed bythe side portions 3 while two spark electrodes 7 with their points 8 areprovided for the pockets formed by the webs 2. The dust 9 isprecipitated in circular areas on the electrodes because of thedirectional effect of the points 8. Although the part of the sparkelectrode on the other side of the point 8 has a rounded spark emittingsurface to produce a precipitation of dust on the opposite wall, thisdust is not shown in the drawing. The individual electrodes are combinedto form the wall 10.

In the gas passageway between the two walls 10, each web dust collectingpocket 2' is served by two emitting electrodes 7 which have their sparkpoints 8 directed toward pocket 2. Each side portion collecting pocket 3is served by one emitting electrode 7 with its spark points directedtoward that pocket.

As shown in FIGURE 1, the spark points 8 on the adjacent emittingelectrodes 7 are positioned at different vertical levels so that theelectrical field interference between the electrodes is limited. Asshown by the dust 9, the collection of dust in web pockets 2 iscollected on a larger effective area of the precipitating electrodebecause of the positioning of the spark points.

Having now described the means by which the objects of the invention areobtained, we claim:

1. An electrostatic dust separator comprising two substantially parallelprecipitating walls spaced from each other and defining a gas passagewaytherebetween; each wall being composed of a row of individualprecipitating electrodes; each said electrode being composed of acentral substantially rectangular planar web, two rectangularsubstantially planar side portions lying substantially in the sameplane, S-shaped bent portion joining each of said side portions toopposite edges of said web and offsetting the plane of said sideportions from the plane of the web, said S-shaped portions being curvedslightly over said web, said side portions being of equal width and eachbeing about one-half the Width of said Web, and edge portions on saidside portions with each edge portion being bent in the form of a hookwhose terminal end is directed toward said web, said individualprecipitating electrodes being alternately faced and hooked together bysaid edge portions and forming a precipitating wall with at least someof said webs and said side portions forming dust collecting pockets; aplurality of spark emitting electrodes having vertically spaced sparkpoints mounted thereon in said gas passageway between said walls withthe spark points of the two emitting electrodes nearest a web directedtoward a Web formed pocket and the spark points of one emittingelectrode nearest a side portion directed toward a side portion formedpocket there being two emitting electrodes operatively associated witheach web formed pocket and one emitting electrode operatively associatedwith each side portion formed pocket; the spark points of adjacentemitting electrodes being positioned at different vertical levels,respectively, and for reducing the interference in the electrical fieldproduced by adjacent spark points.

References Cited UNITED STATES PATENTS 2,195,431 4/1940 Shively et al55-152 X 3,282,029 11/1966 Steuernagel 55-l41 FOREIGN PATENTS 687,858 6/1964 Canada.

70,074 10/ 1949 Denmark.

684,342 11/1939 Germany.

752,566 5/1953 Germany.

858,870 1/1961 Great Britain.

878,869 10/ 1 961 Great Britain.

963,109 7/ 1964 Great Britain.

609,324 9/ 1960 Italy.

OTHER REFERENCES German printed application No. 1,158,043, printedNovember 1963, 1 sheet drawing, 2 pp. specs.

20 FRANK W. LUTIER, Primary Examiner.

D. TALBERT, Assistant Examiner.

